There are always Golden Tube SE40 amps for sale on Audiogon for ridiculously low prices - around $400.00. The SE-40 is
single ended ( pentode ) using 3 5881wxt (6l6GC)tubes per channel with about 40 watts per side.
I see this as a "free trial" economically.
Otherwise if 15 watts is not enough you might have to go up to way more power . I can't recall the formula but I think you need to double the power for each 3db gain you are seeking.
Go with another ASL - specifically the AQ-1006(845). 22 wpc of big 845 power. More than enough, and waaaaay sweeter than KT88s to boot.
SET's that actually do over 30 watts are quite rare and I don't know of any that are less expensive than the Cary. The reason is, very few tubes can deliver over 30 watts.
You might consider an output transformerless tube amp. OTL's do some things better than SET's, and something like the Atma-Sphere M60's (under five grand) would really sing with your speakers. Generally SET's are a bit warmer and sweeter, but OTL's give you the richest inner harmonics of any amplifier type while still being on the warm side. I've had both in my sytem.
I second the OTL idea, alongside the SET one -- and Atmaspheres are quite reliable. However, these don't come cheap either and I wonder whether the Atma 30 (cheaper) couldn't add an extra 3db intensity?
Another constructor is KR; although not cheap, they offer proprietary tubes with alleged 50.000hrs life -- so, no maintenance cost (no rolling either).
Antique Sound Lab also has an 805 based mono single ended amp that delivers 50 watts per channel and is less expensive than the 845 based amp. The word is that the 805 amp is not as sweet sounding as the 845 amp......but it is probably worth an audition in your system if you can find a local dealer with one. You may want to try the Bel Canto 845 based stereo amp that has parallel 845's in a single ended configuration. I have seen these used in the $2k to $3k range.
I also, like the idea of an OTL. Plenty of power and reasonnable output impedances should match well with the Coincidents. There are alternatives, however. For example, adding a subwoofer with a good high pass section to cut off the lows going into the main amp can really open up a tube amp. You can end up with extended, powerful bass and a noticably more open and dynamic presentation above that. Cutting off the lows below say 80 HZ or so at a slope of 24 DB per octave is like adding a couple of DB worth of steady state head room to an amp, even more on dynamic peaks. Spending ~$1500 on a good sub and x-over is a lot less money than the extra ~$3000-4000 it would take to buy that extra couple of DB on the amp side of the sonic equation. Just some thoughts.
Add the Bat VK60 or VK75/75SE to your list. It's single ended bridge, not quite the same, but still a great amp!
Joule Electra Stargate(Retail $5500.00) Atma-Sphere S-30( retail $2850.00)The Atma-Sphere tends to be a little on the lean side of neutral(the M-60's,MA-1's are a lot better in this area. The Stargate however is great, you can dial in feedback if neccessary or leave it 0. Has 4,8& 16 ohm taps and a neutral sound that is dead on.
How about a Manley Neo Classic SE/PP 300B. It can be switched from single ended to Push pull configuration on the fly.
The VAIC 520B output tube can deliver 30w in single SET (in the Classic 52B VAIC amp), and 55W in double SET (in the Reference 52B). VAIC also puts out a 320B double SET (Reference 32B) with 40 watts. The tubes are made in the Czech Republic, and the amps are hand-built in Vicenza Italy by MasterSound. Prices vary from $15,000 to $22,000 approximately (thus, out of your price range, but a few pop up in the European second hand market from time to time, at substantial savings). These amps are very controversial (I once had a conversation with Dr. Kron of KR about the merits of VAIC tubes; and there are some controversies about the Audio Note/VAIC joint venture as well...), but, with modifications, these amps equal the performance of lower wattage SETs, yet can drive "normal" (low efficiency) speakers. I own the 52B variant, and drive 87 dB speakers with no problem. The other alternative I would suggest are WAVAC amps (second hand, if you are lucky).
I own a Transcendent Sound T8 stereo OTL, 25 watts/side into 8 ohms, paired with the Merlin VSM-M, and a pair of Zero autoformers, and never felt wanting for more power. Once you tried OTL, you will not go back to regular amps, tube or SS. Transcendent Sound just came out with a low power OTL kit, $1099 for a 15 watt stereo unit. Looks great and I am sure sounds great too. With the Zeros, you can get away with 15 watts.
Here is a link for info about the Zeros:
Also read about it on the ASOG bulletin board:http://www.condor-connection.org/asog/bbs/index.html
I would second the Manley SE/PP mono blocks. I picked up a pair about a year old for about half price. I also have the Cary 2A3 MB's but wanted a bit more "push" for when I use a pair of speakers other than the AV's. This is a very nice pair of amps and are adjustable from a tonality stand point. Also a big factor (for me at least) is they have the XLR input option and include an IEC fitting. Besides the SET to PP selectability you can also dial in feedback from zero to 10 db via 1 db steps. I am quite impressed with these amps and think you may be so inclined as well.
For more power, the Atma-Sphere amps like the M-60's and my favorite A-S amp, the MA-1's, on the Super Eclipses are just stunning. If you can get the right NOS tubes, good cabling and a very good balanced pre-amp to feed the MA-1's, you will be rewarded. You may have trouble if you don't get those elements right. I struggled.
I have long advocated much more power be used with the Coincident Super Eclipses than their commonly associated SET's and other low-powered tubed amps produce. (See my comments on other Coincident threads.) The Cary SLI-80 integrated amp has been paired with the Supers by several posters on AudiogoN. I currently use the Cary SLAM-100's: 95 triode watts (from beam tubes) with satisfying results indeed.
Interestingly enough, I just received a recommendation from the Supers' manufacturer that the Antique Sound Lab Hurricane DT200 mono blocks work very well with the Supers, Totals, and--believe it not--the highly efficient Victory speakers. The Hurricanes put out a whopping 200 watts! Israel said they are at once powerful, retrieve detail, and retain harmonic and tonal structures very well. Quite an accomplishment in a large amp.
I like SETs in small rooms with intimate music, but if you want the flexibility to go with large orchestral music or rock/pop in larger rooms, a more powerful amp takes over and really does the power-weight-physical-presence thing justice.
KR Audio Antares is 25W SET per side, Kr Audio KT88 is 20W per side, both are very good and real value for the money!
I second the KR Antares. I and two friends own them. They are very good, and a super value. If you have more money, the Wavac MD572 is a 50 watter that is remarkable.
Cary's LX 20 series are excelent. I've got the SEI integrated and have modified it with infini bypass and coupling caps. It's only 20 watts but sounds quite powerful with my Gallo references at 88 db sensitivity at 8 ohms. The better caps improved the subjective power dramatically. The monoblocks have twice the power supply and would be that much better for it even at the same wattage. The only caveat with the LX20s is the KR 300BXLS tube do burn out unexpectedly and KR stopped honoring the warranties, screwing alot of ustomers and Cary as well. Cary had to discontinue the product but they're still available used. I'm just taking reciept on a pair of KR T100 tubes that are a pair of 300Bs in a single tube, offering 25 watts with the possiblity of maybe never burning out because of the improved plate dissipation. Cary gave me a good deal on them and says they're the best 300B type they've heard.
Improving other ancilaries like power cords and cables can also make remarkable differences in subjective sense of power ala clarity and weight of bass, etc.. I'm a big fan of Mapleshade products.
I own a Bel Canto SET40 which is a single ended triode using the 845 output tube. It's rated at 37wpc. It is a great sounding amp. I use them to drive my Vonschweikert VR-7's.
The SET40 is zero feedback design with only 2 stages.
The SET80 is a parallel with 2 845's per side.
KR Audio Antares is an exceptional value at 25wpc it will drive many efficient speakers. It is a great amp
Slawney, I do not think that Dr. Kron is affiliated with Vaic anymore.
I have spoken to the German importer of Kron amps:
www.blackforestaudio.de, they have also an English website.
According to Mr. Kuehn, Dr. Kron has nothing to do with Vaic anymore.
So the initial poster should definitely look into the Double Kronzilla SET amps. These amps with 80 watts per chanel really have "balls". And if you read that it takes about 120 man-hours to build one tube and that Bohemian glass blowers are used to blow the glass body of these tubes, you know that this amp has no equal.
(BTW, I am not affiliated with Kron Enterprises or Balckforestaudio)